package com.company.section4;

/**
 * @author cbf4Life cbf4life@126.com
 * I'm glad to share my knowledge with you all.
 */
public abstract class Command {
    //定义一个子类的全局共享变量
    protected final Receiver receiver;

    //实现类必须定义一个接收者
    public Command(Receiver _receiver) {
        this.receiver = _receiver;
    }

    //每个命令类都必须有一个执行命令的方法
    public abstract void execute();
}
